Electrolyte for primary batteries



UNITED STATES PATENT OFFICE.

GEORGE SEELY ENGLE, OI WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR. TO AMERICAN ELEMENTARY ELECTRIC COMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORATION OF THE DISTRICT OF COLUMBIA.

ELECTROLYTE FOR PRIMARY BATTERIES.

1,356,436; No Drawing. Original application To all wiwm it may concern:

citizen of the United States, residing at perature Washington, District of Columbia, have invented certain new and useful Improvements in Electrolytes for Primary Bat-' teries; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to primary electric batteries, the object of the invention being to provide an improved electrolyte having alkaline characteristics, gelatinous in nature and a minimum causticity and is a division of my former application for process of making alkaline elati-nous electrolyte, filed October 8, 1912, erial No. 724,607 and allowed March 24:, 1915.

A further object is to provide an electrolyte with which the electromotive force of the battery will be maintained and local action reduced when the battery is not in use.

A further object of the invention is to provide an alkaline gelatinous electrolyte which will maintain its moisture content and stability without increasing the internal resistance of the battery.

The battery in which the electrolyte is used is preferably one having zinc positive electrodes and negative electrodes formed of two copper oxlds (cupric oxid and onprous oxid, for example). In the makin of the electrolyte, sodium hydroxid (NaO free from iron and preferably also free from silica is dissolved in water to make a solution of substantially 28 gravity Baum. Cereal or vegetable starch is then mixed with the sodium hydroxid solution. The mixing may be effected by stirring the solution with a glass rod, then the solution is heated with occasional stirring until it reaches a temperature of approximately 180 F. when the heat is immediately shut off and the electrolyte stirred thoroughly and allowed to cool to a temwhere it will still flow and may be poured directly into the cell, in which it further cools and assumes a jelly-like consistency which does not change materially in the use of the cell.

Specification of Letters Patent.

Patented Oct. 19, 1920.

The proportions of sodium hydroxid (NaOH), water and starch may be determinedbyquantitative analysis; thus such analysls shows that t grs; of starch are required to gelatinize 6O minims or 1 dram of water. It also shows that about 10 pounds of sodium hydroxid (NaOH) will make about 4 gallons of electrolyte at 28 gravity Baum. It also shows that it requires onesixth as much starch to gelatinize the alkaline electrolyte 28 gravity Baum as it does to gelatinize water to produce a finished product having about thirty gravity Baum.

0 give a concrete example, 10 pounds of sodium hydroxid (NaOH) requires approximately 2,731 grs. (specifically 2,7230% grs.) of starch to gelatinize it when in a solution of 28 gravity Baum and 1 pound of sodium hydroxid will require approximately 273.1

(specifically 27 3.0%}ggrs. of starch in a solution of 28 gravity aum.

The temperature to which the electrolyte is subjected has been found to be an important factor but it has been found in treating large batches of the material when the heat is cut off after the mass reaches a temperature of 180 F. the temperature may continue to rise a few degrees, possibly to 190 F., but should not be allowed to -ex-.

ceed 190 F. To this extent the temperature of 180 stated is not to be taken as absolute, yet care must be taken, first to raise the temperature to a point, where the gelatinizing of the mass will be effective,

and at the same time it must not be raised to a point where the solution will be discolored or the starch broken down into elements which are formed therefrom at higher temperatures, nor should the temperature be raised to a point where an excessive quantity of moisture will be driven off, thereby increasing the specific gravity of the solution. An increase in temperature above 190 has been found to be injurious,

inasmuch as the efiiciency. of the electrolyte is greatly reduced and an excessive temperature will destroy its usefulness entirely.

The gelatinous electrolyte prevents themixture of oXids from one plate to another, or, more specifically stated, the zinc oxid (ZnO) is held against or in proximity to the positive electrode, thereby in a measure protecting of the positive electrode suflicient to reach the negative plate might occur, thus forming a short circuit, but both of these actions are prevented by the gelatinous electrolyte. In the action of the present battery the ZnO and Na ZnO are held against the positive electrode until solution of the same takes place, this action being local and slow in a gelatinous electrolyte of the character specified. Furthermore, the said zincate being held against the positive plate acts as a protective barrier for preventing the electrode from being attacked so actively, but without reducing the E. M. F. because it is an oxid of the element used for the electrode. By the retardation of the solution of the N a ZnO the whole'electrolyte does not become impregnated at once, thus maintaining the E. M. F. for a much longer period.

While I have specifically described the use of sodium hydroxid (NaOH) as the alkaline ingredient of the electrolyte, I do not wish to be specifically limited thereto, save where so specified in the claims, inasmuch as it is found that other alkaline ingredients may be employed, such, for example, as potassium hydroxid (KOH).

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. A gelatinous alkaline electrolyte forprimary batteries formed of an alkaline hydroxid of approximately 28 gravity Baum with which vegetable starch is combined at a temperature of approximately 180 F. and in quantity substantially less than that required to gelatinize an equal quantity of water. 7

2. A gelatinous alkaline electrolyte for primary batteries formed of sodium hydroxid of approximately 28 gravity Baum with which vegetable starch is combined at a temperature of approximately 180 F. and

in quantity substantially less than that required to gelatinize an equal quantity of water.

3. A gelatinous alkaline electrolyte for primary batteries formed of an alkaline hydroxid of approximately 28 gravity Baum with which vegetable starch is combined at a. temperature of approximately 180 F. and in substantally the proportions of approximately 273.1 grs. of starch to one pound of hydroxid.

4;. A gelatinous alkaline electrolyte for primary batteries formed of an alkaline hydroxid of approximately 28 gravity Baum with which starch is combined at a temperature of approximately 180 F. and in quantity substantially less thanthat required to gelatinize an equal quantity of water.

5. A gelatinous alkaline electrolyte for primary batteries formed of sodium hydroxid of approximately 28 gravity Baum with which starch is combined at a temperature of approximately 180 F. and in quantity substantially less than that required to gelatinize an equal quantity of water.

6. A gelatinous alkaline electrolyte for primary batteries formed of an alkaline hydroxid of approximately 28 gravity Baum with which starch is combined at a tempera ture of approximately 180- F. and in substantially the proportions of approximately 273.1 grs. of starch to one pound of hydroxid.

In testimony whereof I have signed my name to this specification.

GEORGE SEELY ENGLE. 

